1. Technical Field
The disclosure generally relates to illumination devices, and particularly to an illumination device with adjustable light radiation direction and/or light radiation angle.
2. Description of Related Art
Nowadays, light emitting diodes (LEDs) have been used extensively as light sources for illumination devices due to their high luminous efficiency, low power consumption and long lifespan. FIG. 15 is a diagram illustrating a Lambertian light intensity distribution of a conventional LED. The Full Width at Half Maximum (FWHM) of the LED is in a range from about 0 degrees to about 60 degrees, and also in a range from about 300 degrees to about 360 degrees. That is, the FWHM of the LED is about 120 degrees. The LED is used to provide light with unchangeable light intensity distribution, which may diminish the LED in many applications.
Therefore, what is needed is an illumination device that overcomes the described limitations.